Journal articles on the topic 'Lipoproteins Analysis'
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1
Huang, Haibin, Mingqun Lin, Xueqi Wang, Takane Kikuchi, Heather Mottaz, Angela Norbeck, and Yasuko Rikihisa. "Proteomic Analysis of and Immune Responses to Ehrlichia chaffeensis Lipoproteins." Infection and Immunity 76, no. 8 (May 19, 2008): 3405–14. http://dx.doi.org/10.1128/iai.00056-08.
Abstract:
ABSTRACT Ehrlichia chaffeensis is an obligately intracellular gram-negative bacterium and is the etiologic agent of human monocytic ehrlichiosis (HME). Although E. chaffeensis induces the generation of several cytokines and chemokines by leukocytes, E. chaffeensis lacks lipopolysaccharide and peptidoglycan. Bioinfomatic analysis of the E. chaffeensis genome, however, predicted genes encoding 15 lipoproteins and 3 posttranslational lipoprotein-processing enzymes. The present study showed that by use of multidimensional liquid chromatography followed by tandem mass spectrometry, all predicted lipoproteins as well as lipoprotein-processing enzymes were expressed by E. chaffeensis cultured in the human promyelocytic leukemia cell line HL-60. Consistent with this observation, a signal peptidase II inhibitor, globomycin, was found to inhibit E. chaffeensis infection and lipoprotein processing in HL-60 cell culture. To study in vivo E. chaffeensis lipoprotein expression and host immune responses to E. chaffeensis lipoproteins, 13 E. chaffeensis lipoprotein genes were cloned into a mammalian expression vector. When the DNA constructs were inoculated into naïve dogs, or when dogs were infected with E. chaffeensis, the animals developed delayed-type hypersensitivity reactions at cutaneous sites of the DNA construct deposition and serum antibodies to these lipoproteins. This is the first demonstration of lipoprotein expression and elicitation of immune responses by a member of the order Rickettsiales. Multiple lipoproteins expressed by E. chaffeensis in vitro and in vivo may play key roles in pathogenesis and immune responses in HME.
2
Polyakov, L. M., D. V. Sumenkova, R. A. Knyazev, and L. E. Panin. "The analysis of interaction between lipoproteins and steroid hormones." Biomeditsinskaya Khimiya 57, no. 3 (2011): 308–13. http://dx.doi.org/10.18097/pbmc20115703308.
Abstract:
Using the methods of ultracentrifugation, gel-filtration and fluorescence quenching, we demonstrated, that plasma lipoproteins bind steroid hormones and can therefore play a role of their active transport form in an organism. High density lipoproteins have revealed the highest affinity to steroids for. It has been found, that protein component of lipoproteins takes part in the formation of lipoprotein-steroid complex. The apolipoprotein A-I, the main protein component of high density lipoproteins, is responsible for binding of steroid hormones. The calculated constants formation of the complexes of lipoproteins with steroid hormones testifies to specificity of linkage. The results obtained allow to considering real opportunity of transfer of steroid hormones into cell by a receptor-mediated endocytosis in structure of lipoproteins complexes.
3
März, W., R. Siekmeier, H. Scharnagl, U. B. Seiffert, and W. Gross. "Fast lipoprotein chromatography: new method of analysis for plasma lipoproteins." Clinical Chemistry 39, no. 11 (November 1, 1993): 2276–81. http://dx.doi.org/10.1093/clinchem/39.11.2276.
Abstract:
Abstract Fast lipoprotein chromatography (FLPC) is a novel method for quantifying lipoproteins. Plasma proteins are separated by fast-flow gel filtration. Lipoproteins are detected by post-column derivatization with an enzymatic cholesterol reagent. FLPC resolves very-low-, low-, and high-density lipoproteins (VLDL, LDL, and HDL, respectively) and completely separates apolipoprotein Al- and apolipoprotein B-containing lipoproteins. CVs for VLDL-cholesterol, LDL-cholesterol, and HDL-cholesterol are 5.8%, 2.0%, and 1.9%, respectively. We compared FLPC with a combined ultracentrifugation and precipitation method and obtained correlation of r = 0.979, 0.978, and 0.933 for VLDL-cholesterol, LDL-cholesterol, and HDL-cholesterol, respectively. Triglyceride concentrations up to 9.00 g/L did not interfere with the quantification of lipoproteins by FLPC. We conclude that FLPC is a precise and reliable method for the analysis of plasma lipoproteins that complements conventional techniques.
4
Remans, Kim, Ken Vercammen, Josselin Bodilis, and Pierre Cornelis. "Genome-wide analysis and literature-based survey of lipoproteins in Pseudomonas aeruginosa." Microbiology 156, no. 9 (September 1, 2010): 2597–607. http://dx.doi.org/10.1099/mic.0.040659-0.
Abstract:
Pseudomonas aeruginosa is a Gram-negative opportunistic pathogen able to cause acute or chronic infections. Like all other Pseudomonas species, P. aeruginosa has a large genome, >6 Mb, encoding more than 5000 proteins. Many proteins are localized in membranes, among them lipoproteins, which can be found tethered to the inner or the outer membrane. Lipoproteins are translocated from the cytoplasm and their N-terminal signal peptide is cleaved by the signal peptidase II, which recognizes a specific sequence called the lipobox just before the first cysteine of the mature lipoprotein. A majority of lipoproteins are transported to the outer membrane via the LolCDEAB system, while those having an avoidance signal remain in the inner membrane. In Escherichia coli, the presence of an aspartate residue after the cysteine is sufficient to cause the lipoprotein to remain in the inner membrane, while in P. aeruginosa the situation is more complex and involves amino acids at position +3 and +4 after the cysteine. Previous studies indicated that there are 185 lipoproteins in P. aeruginosa, with a minority in the inner membrane. A reanalysis led to a reduction of this number to 175, while new retention signals could be predicted, increasing the percentage of inner-membrane lipoproteins to 20 %. About one-third (62 out of 175) of the lipoprotein genes are present in the 17 Pseudomonas genomes sequenced, meaning that these genes are part of the core genome of the genus. Lipoproteins can be classified into families, including those outer-membrane proteins having a structural role or involved in efflux of antibiotics. Comparison of various microarray data indicates that exposure to epithelial cells or some antibiotics, or conversion to mucoidy, has a major influence on the expression of lipoprotein genes in P. aeruginosa.
5
Storf, Stefanie, Friedhelm Pfeiffer, Kieran Dilks, Zhong Qiang Chen, Saheed Imam, and Mechthild Pohlschröder. "Mutational and Bioinformatic Analysis of Haloarchaeal Lipobox-Containing Proteins." Archaea 2010 (2010): 1–11. http://dx.doi.org/10.1155/2010/410975.
Abstract:
A conserved lipid-modified cysteine found in a protein motif commonly referred to as a lipobox mediates the membrane anchoring of a subset of proteins transported across the bacterial cytoplasmic membrane via the Sec pathway. Sequenced haloarchaeal genomes encode many putative lipoproteins and recent studies have confirmed the importance of the conserved lipobox cysteine for signal peptide processing of three lipobox-containing proteins in the model archaeonHaloferax volcanii. We have extended thesein vivoanalyses to additionalHfx. volcaniisubstrates, supporting our previousin silicopredictions and confirming the diversity of predictedHfx. volcaniilipoproteins. Moreover, using extensive comparative secretome analyses, we identified genes encodining putative lipoproteins across a wide range of archaeal species. While ourin silicoanalyses, supported byin vivodata, indicate that most haloarchaeal lipoproteins are Tat substrates, these analyses also predict that many crenarchaeal species lack lipoproteins altogether and that other archaea, such as nonhalophilic euryarchaeal species, transport lipoproteins via the Sec pathway. To facilitate the identification of genes that encode potential haloarchaeal Tat-lipoproteins, we have developed TatLipo, a bioinformatic tool designed to detect lipoboxes in haloarchaeal Tat signal peptides. Our results provide a strong foundation for future studies aimed at identifying components of the archaeal lipoprotein biogenesis pathway.
6
Mahmoodi, Bakhtawar, Ron Gansevoort, Friso Muntinghe, Robin Dullaart, Hanneke Kluin-Nelemans, Nic Veeger, Inge van Schouwenburg, and Karina Meijer. "Lipid levels do not influence the risk of venous thromboembolism." Thrombosis and Haemostasis 108, no. 11 (2012): 923–29. http://dx.doi.org/10.1160/th12-06-0426.
Abstract:
SummaryStudies on the association between lipid profile and venous thromboembolism (VTE) are inconsistent. This could be caused by classical lipoproteins being inferior to apolipoproteins as markers for VTE risk. Therefore, we examined whether apolipoproteins are more strongly related to VTE than lipoproteins. For this analysis we used the PREVEND prospective community based observational cohort study. Levels of apolipoprotein A1 (ApoA1), apolipoprotein B (ApoB), total cholesterol (TC), high-density lipoprotein (HDL), non-HDL, low-density lipoprotein (LDL), triglycerides (TG), lipoprotein(a), ApoB/ApoA1 and TC/HDL ratio were assessed. Subjects with VTE were identified using databases of the national registries of hospital discharge diagnoses, death certificates, and the regional anticoagulation clinic. Out of 7,627 subjects, 110 developed VTE during a median follow-up of 10.5 years. In both univariate and multivariable analyses no significant associations between apolipoproteins and overall VTE were observed. Of the classical lipoproteins, TC, non-HDL, LDL, TG, and TC/HDL ratio were significantly associated with overall VTE in univariate analysis. Significant associations were no longer present in multivariable analysis. TGL and LDL were significantly associated with unprovoked VTE in univariate analysis. After adjustment for age and sex this significance was lost. No significant associations between (apo-) lipoproteins and provoked VTE were found. We conclude that apolipoproteins are not better in predicting VTE risk than the classical lipoproteins. Our population-based cohort study does not show an association between both apolipoproteins and the classical lipoproteins and VTE risk.
7
Trentalance, A., G. Bruscalupi, L. Conti Devirgiliis, S. Leoni, M. T. Mangiantini, L. Rossini, S. Spagnuolo, and S. K. Erickson. "Changes in lipoprotein binding and uptake by hepatocytes during rat liver regeneration." Bioscience Reports 9, no. 2 (April 1, 1989): 231–41. http://dx.doi.org/10.1007/bf01116000.
Abstract:
The binding and uptake of cholesterol enriched lipoproteins by isolated hepatocytes was decreased at 16 hours after partial hepatectomy, with a tendency to return to control values as the regeneration proceeds. The number of lipoprotein binding sites of total cellular membranes remained similar to control at 16 and 24 hours. The plasma lipoprotein pattern, determined by electrophoretic analysis, showed a lower per cent of very low density lipoproteins (VLDL) and a higher per cent of low density lipoproteins (LDL) at 16 and 24 hours post-partial hepatectomy. At these times, plasma lecithin: cholesterol acyltransferase (LCAT) activity was decreased. It is intriguing to suggest that the regenerating liver could regulated the blood lipoprotein pattern and the uptake of lipoproteins by modulating the surface expression of the receptors.
8
Edelberg, J. M., M. Weissler, and S. V. Pizzo. "Kinetic analysis of the effects of glycosaminoglycans and lipoproteins on urokinase-mediated plasminogen activation." Biochemical Journal 276, no. 3 (June 15, 1991): 785–91. http://dx.doi.org/10.1042/bj2760785.
Abstract:
The glycosaminoglycans (GAGs) heparin, heparan sulphate and chondroitin 6-sulphate stimulate the rate of urokinase activation of human plasminogen. Kinetic analysis of plasminogen activation demonstrates that heparin, heparan sulphate and chondroitin 6-sulphate increased the catalytic rate (Kcat) by 5.3-, 3.5- and 2.5-fold respectively. These stimulatory GAGs had no effect on the affinity of urokinase for plasminogen, since the Km of the reaction is unaltered by the GAGs. The GAGs may enhance the rate of plasminogen activation through an interaction with the catalytic domain of the urokinase, with dissociation constants of approx. 30 nM. Additionally, the lipoproteins, lipoprotein (a) [Lp(a)] and low-density lipoprotein (LDL) inhibit heparin and heparan sulphate stimulation of plasmin formation. Lp(a) is a competitive inhibitor (Kic 20 nM) and LDL is a mixed inhibitor of heparin-enhanced urokinase-mediated plasminogen activation (Kic 24 nM and Kiu 60 nM). These inhibition constants correlate with physiological concentrations of these lipoproteins. These data suggest that these GAGs and lipoproteins may play an important role in vivo in regulating urokinase-mediated plasmin formation.
9
Asmal, A. Cader. "Kinetic Analysis of Lipoproteins." JAMA: The Journal of the American Medical Association 253, no. 7 (February 15, 1985): 978. http://dx.doi.org/10.1001/jama.1985.03350310060015.
10
Asmal, A. C. "Kinetic analysis of lipoproteins." JAMA: The Journal of the American Medical Association 253, no. 7 (February 15, 1985): 978–79. http://dx.doi.org/10.1001/jama.253.7.978.
11
Levels, J. H. M., P. R. Abraham, A. van den Ende, and S. J. H. van Deventer. "Distribution and Kinetics of Lipoprotein-Bound Endotoxin." Infection and Immunity 69, no. 5 (May 1, 2001): 2821–28. http://dx.doi.org/10.1128/iai.69.5.2821-2828.2001.
Abstract:
ABSTRACT Lipopolysaccharide (LPS), the major glycolipid component of gram-negative bacterial outer membranes, is a potent endotoxin responsible for pathophysiological symptoms characteristic of infection. The observation that the majority of LPS is found in association with plasma lipoproteins has prompted the suggestion that sequestering of LPS by lipid particles may form an integral part of a humoral detoxification mechanism. Previous studies on the biological properties of isolated lipoproteins used differential ultracentrifugation to separate the major subclasses. To preserve the integrity of the lipoproteins, we have analyzed the LPS distribution, specificity, binding capacity, and kinetics of binding to lipoproteins in human whole blood or plasma by using high-performance gel permeation chromatography and fluorescent LPS of three different chemotypes. The average distribution of O111:B4, J5, or Re595 LPS in whole blood from 10 human volunteers was 60% (±8%) high-density lipoprotein (HDL), 25% (±7%) low-density lipoprotein, and 12% (±5%) very low density lipoprotein. The saturation capacity of lipoproteins for all three LPS chemotypes was in excess of 200 μg/ml. Kinetic analysis however, revealed a strict chemotype dependence. The binding of Re595 or J5 LPS was essentially complete within 10 min, and subsequent redistribution among the lipoprotein subclasses occurred to attain similar distributions as O111:B4 LPS at 40 min. We conclude that under simulated physiological conditions, the binding of LPS to lipoproteins is highly specific, HDL has the highest binding capacity for LPS, the saturation capacity of lipoproteins for endotoxin far exceeds the LPS concentrations measured in clinical situations, and the kinetics of LPS association with lipoproteins display chemotype-dependent differences.
12
Virella, Gabriel, M. Brooks Derrick, Virginia Pate, Charlyne Chassereau, Suzanne R. Thorpe, and Maria F. Lopes-Virella. "Development of Capture Assays for Different Modifications of Human Low-Density Lipoprotein." Clinical Diagnostic Laboratory Immunology 12, no. 1 (January 2005): 68–75. http://dx.doi.org/10.1128/cdli.12.1.68-75.2005.
Abstract:
ABSTRACT Antibodies to malondialdehyde (MDA)-modified low-density lipoprotein (LDL), copper-oxidized LDL (oxLDL), N ε(carboxymethyl) lysine (CML)-modified LDL, and advanced glycosylation end product (AGE)-modified LDL were obtained by immunization of rabbits with in vitro-modified human LDL preparations. After absorption of apolipoprotein B (ApoB) antibodies, we obtained antibodies specific for each modified lipoprotein with unique patterns of reactivity. MDA-LDL antibodies reacted strongly with MDA-LDL and also with oxLDL. CML-LDL antibodies reacted strongly with CML-LDL and also AGE-LDL. oxLDL antibodies reacted with oxLDL but not with MDA-LDL, and AGE-LDL antibodies reacted with AGE-LDL but not with CML-LDL. Capture assays were set with each antiserum, and we tested their ability to capture ApoB-containing lipoproteins isolated from precipitated immune complexes (IC) and from the supernatants remaining after IC precipitation (free lipoproteins). All antibodies captured lipoproteins contained in IC more effectively than free lipoproteins. Analysis of lipoproteins in IC by gas chromatography-mass spectrometry showed that they contained MDA-LDL and CML-LDL in significantly higher concentrations than free lipoproteins. A significant correlation (r = 0.706, P < 0.019) was obtained between the MDA concentrations determined by chemical analysis and by the capture assay of lipoproteins present in IC. In conclusion, we have developed capture assays for different LDL modifications in human ApoB/E lipoprotein-rich fractions isolated from precipitated IC. This approach obviates the interference of IC in previously reported modified LDL assays and allows determination of the degree of modification of LDL with greater accuracy.
13
Niu, You-Guo, and Rhys D. Evans. "Metabolism of very-low-density lipoprotein and chylomicrons by streptozotocin-induced diabetic rat heart: effects of diabetes and lipoprotein preference." American Journal of Physiology-Endocrinology and Metabolism 295, no. 5 (November 2008): E1106—E1116. http://dx.doi.org/10.1152/ajpendo.90260.2008.
Abstract:
Very-low-density lipoprotein (VLDL) and chylomicrons (CM) are major sources of fatty acid supply to the heart, but little is known about their metabolism in diabetic myocardium. To investigate this, working hearts isolated from control rats and diabetic rats 2 wk following streptozotocin (STZ) injection were perfused with control and diabetic lipoproteins. Analysis of the diabetic lipoproteins showed that both VLDL and CM were altered compared with control lipoproteins; both were smaller and had different apolipoprotein composition. Heparin-releasable lipoprotein lipase (HR-LPL) activity was increased in STZ-induced diabetic hearts, but tissue residual LPL activity was decreased; moreover, diabetic lipoproteins stimulated HR-LPL activity in both diabetic and control hearts. Diabetic hearts oxidized lipoprotein-triacylglycerol (TAG) to a significantly greater extent than controls (>80% compared with deposition as tissue lipid), and the oxidation rate of exogenous lipoprotein-TAG was increased significantly in diabetic hearts regardless of TAG source. Significantly increased intracardiomyocyte TAG accumulation was found in diabetic hearts, although cardiac mechanical function was not inhibited, suggesting that lipotoxicity precedes impaired cardiac performance. Glucose oxidation was significantly decreased in diabetic hearts; additionally, however, diabetic lipoproteins decreased glucose oxidation in diabetic and control hearts. These results demonstrate increased TAG-rich lipoprotein metabolism concomitant with decreased glucose oxidation in type 1 diabetic hearts, and the alterations in cardiac lipoprotein metabolism may be due to the properties of diabetic TAG-rich lipoproteins as well as the diabetic state of the myocardium. These changes were not related to cardiomyopathy at this early stage of diabetes.
14
Okazaki, Mitsuyo, Shinichi Usui, Akio Fukui, Isao Kubota, and Hitonobu Tomoike. "Component Analysis of HPLC Profiles of Unique Lipoprotein Subclass Cholesterols for Detection of Coronary Artery Disease." Clinical Chemistry 52, no. 11 (November 1, 2006): 2049–53. http://dx.doi.org/10.1373/clinchem.2006.070094.
Abstract:
Abstract Background: Patients with coronary artery disease (CAD) are known to have several lipoprotein abnormalities. We examined plasma cholesterol concentrations of major lipoproteins and their subclasses, using a gel permeation HPLC, to establish an association between a lipoprotein subclass pattern and the presence of CAD. Methods: We performed a simple and fully automated HPLC, followed by mathematical treatment on chromatograms, for measuring cholesterol concentrations of major lipoproteins and their subclasses in 62 male patients (45 with CAD and 17 controls without CAD) who underwent cardiac catheterization. Results: For major lipoprotein classes, the patient group had a significantly (P <0.05) higher LDL-cholesterol (LDL-C) and lower HDL-cholesterol (HDL-C), but no difference in VLDL-cholesterol (VLDL-C) concentrations. For lipoprotein subclasses, the patient group had a significantly higher small VLDL-C (mean particle diameter of 31.3 nm, P <0.001), small LDL-C (23.0 nm, P <0.05), and very small LDL-C (16.7–20.7 nm, P <0.001), but a significantly lower large HDL-C (12.1 nm, P <0.001) concentrations. Combined variables of “small VLDL-C + small LDL-C + very small LDL-C – large HDL-C” differentiated the patient from the control group more clearly than single-subclass measurements or calculated traditional lipid markers. Conclusions: These results suggest the usefulness of multiple and simultaneous subclass analysis of proatherogenic and antiatherogenic lipoproteins and indicate that HPLC and its component analysis can be used for easy detection and evaluation of abnormal distribution of lipoprotein subclasses associated with CAD.
15
Collins, Lisamarie A., Shama P. Mirza, Ahmed H. Kissebah, and Michael Olivier. "Integrated approach for the comprehensive characterization of lipoproteins from human plasma using FPLC and nano-HPLC-tandem mass spectrometry." Physiological Genomics 40, no. 3 (February 2010): 208–15. http://dx.doi.org/10.1152/physiolgenomics.00136.2009.
Abstract:
The implication of the various lipoprotein classes in the development of atherosclerotic cardiovascular disease has served to focus a great deal of attention on these particles over the past half-century. Using knowledge gained by the sequencing of the human genome, recent research efforts have been directed toward the elucidation of the proteomes of several lipoprotein subclasses. One of the challenges of such proteomic experimentation is the ability to initially isolate plasma lipoproteins subsequent to their analysis by mass spectrometry. Although several methods for the isolation of plasma lipoproteins are available, the most commonly utilized techniques require large sample volumes and may cause destruction and dissociation of lipoprotein particle-associated proteins. Fast protein liquid chromatography (FPLC) is a nondenaturing technique that has been validated for the isolation of plasma lipoproteins from relatively small sample volumes. In this study, we present the use of FPLC in conjunction with nano-HPLC-ESI-tandem mass spectrometry as a new integrated methodology suitable for the proteomic analysis of human lipoprotein fractions. Results from our analysis show that only 200 μl of human plasma suffices for the isolation of whole high density lipoprotein (HDL) and the identification of the majority of all known HDL-associated proteins using mass spectrometry of the resulting fractions.
16
Babu, M. Madan, M. Leena Priya, A. Tamil Selvan, Martin Madera, Julian Gough, L. Aravind, and K. Sankaran. "A Database of Bacterial Lipoproteins (DOLOP) with Functional Assignments to Predicted Lipoproteins." Journal of Bacteriology 188, no. 8 (April 15, 2006): 2761–73. http://dx.doi.org/10.1128/jb.188.8.2761-2773.2006.
Abstract:
ABSTRACT Lipid modification of the N-terminal Cys residue (N-acyl-S-diacylglyceryl-Cys) has been found to be an essential, ubiquitous, and unique bacterial posttranslational modification. Such a modification allows anchoring of even highly hydrophilic proteins to the membrane which carry out a variety of functions important for bacteria, including pathogenesis. Hence, being able to identify such proteins is of great value. To this end, we have created a comprehensive database of bacterial lipoproteins, called DOLOP, which contains information and links to molecular details for about 278 distinct lipoproteins and predicted lipoproteins from 234 completely sequenced bacterial genomes. The website also features a tool that applies a predictive algorithm to identify the presence or absence of the lipoprotein signal sequence in a user-given sequence. The experimentally verified lipoproteins have been classified into different functional classes and more importantly functional domain assignments using hidden Markov models from the SUPERFAMILY database that have been provided for the predicted lipoproteins. Other features include the following: primary sequence analysis, signal sequence analysis, and search facility and information exchange facility to allow researchers to exchange results on newly characterized lipoproteins. The website, along with additional information on the biosynthetic pathway, statistics on predicted lipoproteins, and related figures, is available at http://www.mrc-lmb.cam.ac.uk/genomes/dolop/ .
17
Suomela, Jukka-Pekka, Markku Ahotupa, Olli Sjövall, Juha-Pekka Kurvinen, and Heikki Kallio. "Diet and lipoprotein oxidation: Analysis of oxidized triacylglycerols in pig lipoproteins." Lipids 39, no. 7 (July 2004): 639–47. http://dx.doi.org/10.1007/s11745-004-1277-4.
18
Bourgeois, R., A. A. Després, J. Guertin, N. Perrot, P. Mitchell, C. Gotti, S. Bourassa, et al. "A Comparative Proteomic Analysis Of Lipoprotein(A) And Low-Density Lipoproteins." Atherosclerosis 287 (August 2019): e58. http://dx.doi.org/10.1016/j.atherosclerosis.2019.06.163.
19
Otvos, J. D., E. J. Jeyarajah, L. W. Hayes, D. S. Freedman, N. A. Janjan, and T. Anderson. "Relationships between the proton nuclear magnetic resonance properties of plasma lipoproteins and cancer." Clinical Chemistry 37, no. 3 (March 1, 1991): 369–76. http://dx.doi.org/10.1093/clinchem/37.3.369.
Abstract:
Abstract We conducted a comprehensive investigation of the origin of nuclear magnetic resonance (NMR) lineshape variability of plasma lipids among healthy individuals and those with cancer. The methyl and methylene resonances of lipid in human plasma, whose linewidths have been reported to correlate with the presence of malignancy, are composed of the overlapping resonances of "mobile" protons from the major lipoproteins (very-low-, low-, and high-density lipoproteins). We tested two hypotheses for the origin of the narrower plasma linewidths observed for cancer patients: (a) malignancy-associated differences in the spectral properties (chemical shift, lineshape) of one or more of the lipoproteins, and (b) differences in the fraction of lipoprotein lipid giving rise to detectable NMR signal. Analysis of the concentrations of lipoprotein lipid and of 500 MHz NMR spectra of the lipoprotein constituents in greater than 100 plasma samples failed to provide support for either hypothesis. Although linewidths were found to be significantly narrower for the cancer group, the difference is entirely attributable to differences in the concentrations of the lipoproteins.
20
Grundy, Scott M. "Kinetic Analysis of Lipoproteins-Reply." JAMA: The Journal of the American Medical Association 253, no. 7 (February 15, 1985): 978. http://dx.doi.org/10.1001/jama.1985.03350310060016.
21
Otvos, J. D., E. J. Jeyarajah, and D. W. Bennett. "Quantification of plasma lipoproteins by proton nuclear magnetic resonance spectroscopy." Clinical Chemistry 37, no. 3 (March 1, 1991): 377–86. http://dx.doi.org/10.1093/clinchem/37.3.377.
Abstract:
Abstract A new analytical procedure for quantifying plasma lipoproteins by proton nuclear magnetic resonance (NMR) spectroscopy has been developed that potentially offers significant advantages over existing clinical methods used for assessing risk of coronary heart disease. Analysis of a single spectrum of a nonfasting plasma sample, acquired simply and rapidly at moderate magnetic field strength (250 MHz), yields a complete profile of lipoprotein concentrations: chylomicrons and very-low-, low-, and high-density lipoproteins. The method is based on curve-fitting (spectral deconvolution) of the plasma methyl lipid resonance envelope, the amplitude and shape of which depend directly on the amplitudes of the superimposed methyl resonances of the lipoprotein components. A linear least-squares curve-fitting algorithm was developed to efficiently extract the signal amplitudes (concentrations) of the lipoproteins from the plasma spectrum. These signal amplitudes correlate well with lipoprotein concentrations determined by triglyceride and cholesterol measurements.
22
Rose, Jeffrey R., Maureen A. Mullarkey, William J. Christ, Lynn D. Hawkins, Melvyn Lynn, Yoshito Kishi, Kishor M. Wasan, Kathy Peteherych, and Daniel P. Rossignol. "Consequences of Interaction of a Lipophilic Endotoxin Antagonist with Plasma Lipoproteins." Antimicrobial Agents and Chemotherapy 44, no. 3 (March 1, 2000): 504–10. http://dx.doi.org/10.1128/aac.44.3.504-510.2000.
Abstract:
ABSTRACT E5531, a novel synthetic lipid A analogue, antagonizes the toxic effects of lipopolysaccharide, making it a potential intravenously administered therapeutic agent for the treatment of sepsis. This report describes the distribution of E5531 in human blood and its activity when it is associated with different lipoprotein subclasses. After in vitro incubation of [14C]E5531 with blood, the great majority (>92%) of material was found in the plasma fraction. Analysis by size-exclusion and affinity chromatographies and density gradient centrifugation indicates that [14C]E5531 binds to lipoproteins, primarily high-density lipoproteins (HDLs), with distribution into low-density lipoproteins (LDLs) and very low density lipoproteins (VLDLs) being dependent on the plasma LDL or VLDL cholesterol concentration. Similar results were also seen in a limited study of [14C]E5531 administration to human volunteers. The potency of E5531 in freshly drawn human blood directly correlates to increasing LDL cholesterol levels. Finally, preincubation of E5531 with plasma or purified lipoproteins indicated that binding to HDL resulted in a time-dependent loss of drug activity. This loss in activity was not observed with drug binding to LDLs or to VLDLs or chylomicrons. Taken together, these results indicate that E5531 binds to plasma lipoproteins, making its long-term antagonistic potency dependent on the plasma lipoprotein composition.
23
Renee Ruhaak, L., Arnoud van der Laarse, and Christa M. Cobbaert. "Apolipoprotein profiling as a personalized approach to the diagnosis and treatment of dyslipidaemia." Annals of Clinical Biochemistry: International Journal of Laboratory Medicine 56, no. 3 (March 19, 2019): 338–56. http://dx.doi.org/10.1177/0004563219827620.
Abstract:
An elevated low-density lipoprotein cholesterol concentration is a classical risk factor for cardiovascular disease. This has led to pharmacotherapy in patients with atherosclerotic heart disease or high heart disease risk with statins to reduce serum low-density lipoprotein cholesterol. Even in patients in whom the target levels of low-density lipoprotein cholesterol are reached, there remains a significant residual cardiovascular risk; this is due, in part, to a focus on low-density lipoprotein cholesterol alone and neglect of other important aspects of lipoprotein metabolism. A more refined lipoprotein analysis will provide additional information on the accumulation of very low-density lipoproteins, intermediate density lipoproteins, chylomicrons, chylomicron-remnants and Lp(a) concentrations. Instead of measuring the cholesterol and triglyceride content of the lipoproteins, measurement of their apolipoproteins (apos) is more informative. Apos are either specific for a particular lipoprotein or for a group of lipoproteins. In particular measurement of apos in atherogenic particles is more biologically meaningful than the measurement of the cholesterol concentration contained in these particles. Applying apo profiling will not only improve characterization of the lipoprotein abnormality, but will also improve definition of therapeutic targets. Apo profiling aligns with the concept of precision medicine by which an individual patient is not treated as ‘average’ patient by the average (dose of) therapy. This concept of precision medicine fits the unmet clinical need for stratified cardiovascular medicine. The requirements for clinical application of proteomics, including apo profiling, can now be met using robust mass spectrometry technology which offers desirable analytical performance and standardization.
24
Otvos, J. D., E. J. Jeyarajah, D. W. Bennett, and R. M. Krauss. "Development of a Proton Nuclear Magnetic Resonance Spectroscopic Method for Determining Plasma Lipoprotein Concentrations and Subspecies Distributions from a Single, Rapid Measurement." Clinical Chemistry 38, no. 9 (September 1, 1992): 1632–38. http://dx.doi.org/10.1093/clinchem/38.9.1632.
Abstract:
Abstract We are developing a method for quantifying plasma lipoproteins by proton nuclear magnetic resonance (NMR) spectroscopy that offers advantages over existing clinical methods. We showed that the major lipoproteins have distinct NMR properties sufficient to permit their concentrations to be extracted from a computer lineshape analysis of the plasma lipid methyl resonance envelope (Clin Chem 1991; 37:377-86). We have now discovered that the spectra of the subspecies within each lipoprotein class are different enough to influence the composite spectrum of that class and hence the spectrum of whole plasma. By including spectra representative of these subspecies as additional components in the lineshape-fitting analysis, a complete concentration profile of very-low-density, low-density (LDL), and high-density (HDL) lipoproteins plus the subspecies distributions within these classes can be simultaneously generated. A pilot study of 30 plasma samples of widely varied composition demonstrated good agreement between NMR-derived values and lipoprotein lipid concentrations and LDL and HDL subspecies distributions determined by gradient-gel electrophoresis.
25
Takahashi, M., Y. Yui, H. Yasumoto, T. Aoyama, H. Morishita, R. Hattori, and C. Kawai. "Lipoproteins are inhibitors of endothelium-dependent relaxation of rabbit aorta." American Journal of Physiology-Heart and Circulatory Physiology 258, no. 1 (January 1, 1990): H1—H8. http://dx.doi.org/10.1152/ajpheart.1990.258.1.h1.
Abstract:
The present study was performed to investigate plasma inhibitors of endothelium-dependent relaxation other than hemoglobin and low-density lipoprotein (LDL). We purified an inhibitor that contained a protein of 28,000 Da from human plasma by ammonium sulfate precipitation and serial chromatography. NH2-terminal sequence analysis revealed the protein to be homologous with human apolipoprotein A-I (Apo A-I), a major apolipoprotein of high-density lipoprotein (HDL). Very low-density lipoprotein (VLDL), LDL, and HDL obtained from rabbit plasma reversed endothelium-dependent relaxation of rabbit aorta induced by acetylcholine (ACh) and A23187 but did not inhibit relaxations induced by nitroglycerin or nitric oxide. These inhibitory activities were lost by delipidation of lipoproteins, and there were no differences in the inhibitory activity among these three lipoproteins on the basis of phospholipid concentration. Moreover, phospholipids such as phosphatidylcholine, phosphatidylinositol, and sphingomyelin reversed relaxations by ACh and A23187. Thus all lipoproteins inhibit endothelium-dependent relaxation, and this nonspecific inhibition seems to be due to the inhibition of production or release of endothelium-derived relaxing factor by phospholipids in the lipoprotein complex.
26
Adam, Lynda, and Louise Brissette. "Analysis of the lipoprotein binding site of rat liver membranes." Biochemistry and Cell Biology 72, no. 3-4 (March 1, 1994): 132–42. http://dx.doi.org/10.1139/o94-020.
Abstract:
Intermediate density lipoproteins (IDL) were shown to bind to high- and low-affinity binding sites on rat liver membranes. The low-affinity sites were named lipoprotein binding sites (LBS), since they bind all classes of lipoproteins. This study was undertaken to further characterize the interaction of 125I-labelled IDL with the LBS of rat liver membranes to determine the chemical nature of the LBS. We found that the binding of IDL to the LBS is insensitive to EDTA and sensitive to heparin and that it is present on plasma membranes. Also, membranes were pretreated with various enzymes that have an effect on the membrane constituents, and the activity of the LBS on these treated membranes was determined. Our results reveal that the LBS of rat liver membranes is insensitive to heparinase I, chondroitinase ABC, and phospholipase C, while it is partially sensitive to phospholipase A2 and sensitive to proteases and heat. Rat liver membrane proteins were solubilized with Triton X-100, reconstituted in liposomes, and analyzed for their ability to bind lipoproteins. 125I-labelled IDL were shown to bind to high- and low-affinity sites that are similar, in affinity and specificity, to the ones observed with intact rat liver membranes, indicating that a LBS activity is detectable on these liposomes. We found that the binding capacity of low-affinity sites in liposomes containing either no protein or containing proteins solubilized from Escherichia coli membranes is five times weaker than low-affinity sites in liposomes containing liver membrane proteins. Thus, a protein solubilized from rat liver membranes has LBS activity when reconstituted in liposomes. Taken altogether our results provide new information on the binding of IDL to the LBS and indicate that the LBS activity is in part mediated by a protein. Thus, the LBS appears to be a bona fide receptor.Key words: lipoprotein, receptor, binding, metabolism.
27
Denham, E. L., P. N. Ward, and J. A. Leigh. "In the absence of Lgt, lipoproteins are shed from Streptococcus uberis independently of Lsp." Microbiology 155, no. 1 (January 1, 2009): 134–41. http://dx.doi.org/10.1099/mic.0.022061-0.
Abstract:
The role of lipoprotein diacylglyceryl transferase (Lgt) and lipoprotein signal peptidase (Lsp) responsible for processing lipoproteins was investigated in Streptococcus uberis, a common cause of bovine mastitis. In the absence of Lgt, three lipoproteins [MtuA (SUB0473), Hap (SUB1625) and an extracellular solute-binding protein (SUB0365)] were detected in extracellular locations. All were shown by Edman degradation analysis to be cleaved on the carboxy side of the LXXC lipobox. Detection of MtuA, a lipoprotein shown previously to be essential for infectivity and virulence, was used as a surrogate lipoprotein marker to locate and assess processing of lipoproteins. The absence of Lgt did not prevent location of MtuA to the cell membrane, its location in the wild-type strain but, in contrast to the situation with wild-type, did result in a widespread location of this protein. In the absence of both Lgt and Lsp, MtuA was similarly released from the bacterial cell. In such strains, however, the cell-associated MtuA represented the full-length gene product, indicating that Lsp was able to cleave non-lipidated (lipo)proteins but was not responsible for their release from this bacterium.
28
Fukushima, Keizo, Shinji Kobuchi, Masakazu Shibata, Kanji Takada, and Nobuyuki Sugioka. "Decrease in Brain Distribution of Fluvoxamine in Experimental Hyperlipidemic Rats." Journal of Pharmacy & Pharmaceutical Sciences 14, no. 3 (November 2, 2011): 414. http://dx.doi.org/10.18433/j3vg6t.
Abstract:
ABSTRACT: Purpose. Many clinical reports and trials have suggested that fluvoxamine (FLV) reduces plasma lipoprotein levels. However, few studies have reported the effect of plasma lipoproteins on FLV pharmacokinetics. The aim of the present study was to investigate the affinities of FLV to plasma lipoproteins and the effect of plasma lipoproteins on the biodistribution of FLV using an experimental hyperlipidemic (HL) rat model. Methods. HL rats were prepared by intraperitoneal administration of Poloxamer-407 solution (1.0 g/kg). In vitro protein binding and distribution of FLV in plasma lipoproteins were determined in control and HL rats. In vivo pharmacokinetic study (intravenous administration of FLV, 5.0 mg/kg) and biodistribution analysis for brain and liver at a steady state (infusion, 1.5 mg/kg/hr, 6 hrs) were also performed. Results. The plasma protein binding of FLV was around 83% and 95% in control and HL rats, respectively, whereas the FLV recoveries in triglyceride-rich lipoprotein fractions were increased in HL. Therefore, the elevation of lipoproteins was likely responsible for the increase in protein binding in HL. After intravenous administration, the area under the plasma concentration vs. time curve (AUC) in HL was 3.9-fold greater than that in control rats, whereas the distribution ratio of FLV plasma concentration to the brain at a steady state was decreased to approximately 20% of that of the control. Conclusions. FLV has an affinity to plasma lipoproteins, and their elevation might decrease the FLV biodistribution to brain; the plasma lipoprotein levels could not be found to correlate positively with the FLV pharmacokinetic effect in brain, but rather may attenuate it.
This article is open to POST-PUBLICATION REVIEW. Registered readers (see “For Readers”) may comment by clicking on ABSTRACT on the issue’s contents page.
29
Denham, E. L., P. N. Ward, and J. A. Leigh. "Lipoprotein Signal Peptides Are Processed by Lsp and Eep of Streptococcus uberis." Journal of Bacteriology 190, no. 13 (May 9, 2008): 4641–47. http://dx.doi.org/10.1128/jb.00287-08.
Abstract:
ABSTRACT Lipoprotein signal peptidase (lsp) is responsible for cleaving the signal peptide sequence of lipoproteins in gram-positive bacteria. Investigation of the role of Lsp in Streptococcus uberis, a common cause of bovine mastitis, was undertaken using the lipoprotein MtuA (a protein essential for virulence) as a marker. The S. uberis lsp mutant phenotype displayed novel lipoprotein processing. Not only was full-length (uncleaved) MtuA detected by Western blotting, but during late log phase, a lower-molecular-weight derivative of MtuA was evident. Similar analysis of an S. uberis double mutant containing insertions disrupting both lsp and eep (a homologue of the Enterococcus faecalis “enhanced expression of pheromone” gene) indicated a role for eep in cleavage of lipoproteins in the absence of Lsp. Such a function may indicate a role for eep in maintenance of secretion pathways during disruption of normal lipoprotein processing.
30
Fernández-Cidón, Bárbara, Beatriz Candás-Estébanez, Miriam Gil-Serret, Núria Amigó, Emili Corbella, M. Ángeles Rodríguez-Sánchez, Ariadna Padró-Miquel, et al. "Physicochemical Properties of Lipoproteins Assessed by Nuclear Magnetic Resonance as a Predictor of Premature Cardiovascular Disease. PRESARV-SEA Study." Journal of Clinical Medicine 10, no. 7 (March 29, 2021): 1379. http://dx.doi.org/10.3390/jcm10071379.
Abstract:
Some lipoprotein disorders related to the residual risk of premature cardiovascular disease (PCVD) are not detected by the conventional lipid profile. In this case-control study, the predictive power of PCVD of serum sdLDL-C, measured using a lipoprotein precipitation method, and of the physicochemical properties of serum lipoproteins, analyzed by nuclear magnetic resonance (NMR) techniques, were evaluated. We studied a group of patients with a first PCVD event (n = 125) and a group of control subjects (n = 190). Conventional lipid profile, the size and number of Very Low Density Lipoproteins (VLDL), Low Density Lipoproteins (LDL), High Density Lipoproteins (HDL) particles, and the number of particles of their subclasses (large, medium, and small) were measured. Compared to controls, PCVD patients had lower concentrations of all LDL particles, and smaller and larger diameter of LDL and HDL particles, respectively. PCVD patients also showed higher concentrations of small dense LDL-cholesterol (sdLDL), and triglycerides (Tg) in LDL and HDL particles (HDL-Tg), and higher concentrations of large VLDL particles. Multivariate logistic regression showed that sdLDL-C, HDL-Tg, and large concentrations of LDL particles were the most powerful predictors of PCVD. A strong relationship was observed between increased HDL-Tg concentrations and PCVD. This study demonstrates that beyond the conventional lipid profile, PCVD patients have other atherogenic lipoprotein alterations that are detected by magnetic resonance imaging (MRI) analysis.
31
Yamauchi, Kazuyoshi, Minoru Tozuka, Hiroya Hidaka, Eiko Hidaka, Yoshiyuki Kondo, and Tsutomu Katsuyama. "Characterization of Apolipoprotein E-containing Lipoproteins in Cerebrospinal Fluid: Effect of Phenotype on the Distribution of Apolipoprotein E." Clinical Chemistry 45, no. 9 (September 1, 1999): 1431–38. http://dx.doi.org/10.1093/clinchem/45.9.1431.
Abstract:
Abstract Background: Apolipoprotein (apo) E, one of the main apolipoproteins in the central nervous system, may play an important role in lipid metabolism; however, the details of its function are poorly understood. In this study, we characterized apoE-containing lipoproteins in cerebrospinal fluid (CSF) and examined the effect of apoE phenotype on the distribution of apoE among the lipoprotein fractions. Methods: CSF lipoproteins were fractionated by gel filtration and ultracentrifugation, and then characterized by electrophoresis, immunoblot, electron microscopy, and analysis of apoE, total cholesterol, and phospholipid concentrations. Results: The ratio of sialylated to nonsialylated apoE was higher in CSF than in serum. However, the fundamental forms containing apoE homodimers or heterodimers [such as apo(E-AII) and apo(AII-E2-AII) complexes] were similar in CSF and serum. apoE-containing lipoproteins were fractionated at densities of <1.006, 1.063–1.125, and 1.125–1.21 kg/L. Neither apoE nor apoAI was detected in the fraction with a density range of 1.006–1.063 kg/L. The diameters of the lipoprotein particles with densities of <1.006, 1.063–1.125, and 1.125–1.21 kg/L were 16.7 ± 3.1, 14.0 ± 3.2, and 11.6 ± 2.8 nm (mean ± SD, n = 200), respectively. All of these lipoproteins exhibited a spherical structure. The distribution profile of apoE-containing lipoproteins was affected by the apoE phenotype. A relatively large amount of apoE-containing lipoproteins was isolated from the fraction with a density >1.125 kg/L obtained from CSF associated with apoE2 or apoE3. This tendency was more obvious in CSF associated with apoE2 than in CSF without apoE2. apoE-containing lipoproteins were predominantly observed in the fraction with a density of <1.006 kg/L obtained from CSF associated with apoE4. Conclusions: The lipoproteins in CSF have a unique composition that is different from that of the lipoproteins in plasma. However, the differences in diameter between the CSF fractions were not as large as for the serum fractions. Our data suggest that the apoE phenotype may affect the distribution profile of apoE-containing lipoproteins in the CSF. This would mean that the metabolism of apoE-containing lipoproteins depends on the apoE isoform present.
32
Papadopulo, I., F. de La Farge, J. P. Braun, P. Valdiguié, and A. G. Rico. "Analysis for lipoproteins in horse serum." Clinical Chemistry 33, no. 6 (June 1, 1987): 1081. http://dx.doi.org/10.1093/clinchem/33.6.1081.
33
Barrie, J., A. S. Nash, and T. D. G. Watson. "Quantitative analysis of canine plasma lipoproteins." Journal of Small Animal Practice 34, no. 5 (May 1993): 226–31. http://dx.doi.org/10.1111/j.1748-5827.1993.tb02671.x.
34
Fruchart, J. C. "Molecular analysis of lipoproteins ? clinical application." Fresenius' Journal of Analytical Chemistry 343, no. 1 (1992): 35. http://dx.doi.org/10.1007/bf00331974.
35
Mešalić, Lejla, and Edhem Hasković. "Analysis of lipid status, body mass index and waist-hip ratio in post-menopausal women." Journal of Health Sciences 2, no. 2 (September 15, 2012): 122–26. http://dx.doi.org/10.17532/jhsci.2012.49.
Abstract:
Introduction: Menopause is the absence of menses in the period longer that one year. It is widely accepted that menopause leads to changes in hormonal status, metabolism and lipid profi le. The aim of this study wasto analyze the infl uence of menopause on the concentrations of lipids, lipoproteins and also the influence of body mass index (BMI) and waist-hip ratio (WHR) on lipid profi le in post-menopausal women.Methods: Sixty post-menopausal women of average age of 52.82 years were compared to a group of 34 pre-menopausal women average age of 47.92 years.Results: Post-menopausal women had higher, but non signifi cant (p>0.05) concentrations of total cholesterol, very low density lipoproteins (VLDL), low density lipoproteins (LDL) and triglycerides than pre-menopausal women. The concentration of high density lipoproteins (HDL) was significantly lower in post-menopausal women than pre-menopausal (p<0.05). The concentration of apolipoprotein B was also signifi cantly higher in post-menopausal women (p<0.05), but the concentrations of apolipoprotein and lipoprotein (a) were lowerbut without signifi cance (p>0.05). There was no difference between body mass index (BMI) and waste-hip ratio (WHR), but the WHR has shown as a signifi cant predictor of the LDL and cholesterol concentrations inpost-menopausal women.Conclusion: We can conclude that menopause leads to changes in lipid profi le by lowering of HDL and increasing the levels of apolipoprotein B, that increases the risk for cardiovascular disease. The WHR is thesignifi cant predictor of cardiovascular risk in post-menopausal women.
36
Rajalahti, Tarja, Eivind Aadland, Geir Kåre Resaland, Sigmund Alfred Anderssen, and Olav Martin Kvalheim. "Cardiometabolic Associations between Physical Activity, Adiposity, and Lipoprotein Subclasses in Prepubertal Norwegian Children." Nutrients 13, no. 6 (June 19, 2021): 2095. http://dx.doi.org/10.3390/nu13062095.
Abstract:
Lipoprotein subclasses possess crucial cardiometabolic information. Due to strong multicollinearity among variables, little is known about the strength of influence of physical activity (PA) and adiposity upon this cardiometabolic pattern. Using a novel approach to adjust for covariates, we aimed at determining the “net” patterns and strength for PA and adiposity to the lipoprotein profile. Principal component and multivariate pattern analysis were used for the analysis of 841 prepubertal children characterized by 26 lipoprotein features determined by proton nuclear magnetic resonance spectroscopy, a high-resolution PA descriptor derived from accelerometry, and three adiposity measures: body mass index, waist circumference to height, and skinfold thickness. Our approach focuses on revealing and validating the underlying predictive association patterns in the metabolic, anthropologic, and PA data to acknowledge the inherent multicollinear nature of such data. PA associates to a favorable cardiometabolic pattern of increased high-density lipoproteins (HDL), very large and large HDL particles, and large size of HDL particles, and decreasedtriglyceride, chylomicrons, very low-density lipoproteins (VLDL), and their subclasses, and to low size of VLDL particles. Although weakened in strength, this pattern resists adjustment for adiposity. Adiposity is inversely associated to this pattern and exhibits unfavorable associations to low-density lipoprotein (LDL) features, including atherogenic small and very small LDL particles. The observed associations are still strong after adjustment for PA. Thus, lipoproteins explain 26.0% in adiposity after adjustment for PA compared to 2.3% in PA after adjustment for adiposity.
37
Novotny, WF, M. Palmier, TC Wun, GJ Jr Broze, and JP Miletich. "Purification and properties of heparin-releasable lipoprotein- associated coagulation inhibitor." Blood 78, no. 2 (July 15, 1991): 394–400. http://dx.doi.org/10.1182/blood.v78.2.394.394.
Abstract:
Abstract The lipoprotein-associated coagulation inhibitor (LACI) is present in vivo in at least three different pools: sequestered in platelets, associated with plasma lipoproteins, and released into plasma by intravenous heparin, possibly from vascular endothelium. In this study we have purified the heparin-relesable form of LACI from post-heparin plasma and show that it is structurally different from lipoprotein LACI. The purification scheme uses heparin-agarose chromatography, immunoaffinity chromatography, and size-exclusion chromatography and results in a 185,000-fold purification with a 33% yield. Heparin- releasable LACI (HRL), as analyzed by sodium dodecyl sulfate- polyacrylamide gel electrophoresis, under reducing conditions, appears as a major band at 40 Kd and a minor band at 36 Kd. Immunoblot analysis suggests that the 36-Kd band arises from carboxyl-terminus proteolysis that occurs during the purification. HRL has a specific activity similar to that of HepG2 or lipoprotein LACI. HRL and lipoprotein LACI combine with lipoproteins in vitro while purified HepG2 LACI does not. I125-labeled HRL, injected into a rabbit, is cleared more slowly than I125-labeled HepG2 LACI, which may be due to attachment to lipoproteins in vivo. Preliminary evidence suggests that HRL is associated with vascular endothelium, possibly by attachment to glycosaminoglycans.
38
Novotny, WF, M. Palmier, TC Wun, GJ Jr Broze, and JP Miletich. "Purification and properties of heparin-releasable lipoprotein- associated coagulation inhibitor." Blood 78, no. 2 (July 15, 1991): 394–400. http://dx.doi.org/10.1182/blood.v78.2.394.bloodjournal782394.
Abstract:
The lipoprotein-associated coagulation inhibitor (LACI) is present in vivo in at least three different pools: sequestered in platelets, associated with plasma lipoproteins, and released into plasma by intravenous heparin, possibly from vascular endothelium. In this study we have purified the heparin-relesable form of LACI from post-heparin plasma and show that it is structurally different from lipoprotein LACI. The purification scheme uses heparin-agarose chromatography, immunoaffinity chromatography, and size-exclusion chromatography and results in a 185,000-fold purification with a 33% yield. Heparin- releasable LACI (HRL), as analyzed by sodium dodecyl sulfate- polyacrylamide gel electrophoresis, under reducing conditions, appears as a major band at 40 Kd and a minor band at 36 Kd. Immunoblot analysis suggests that the 36-Kd band arises from carboxyl-terminus proteolysis that occurs during the purification. HRL has a specific activity similar to that of HepG2 or lipoprotein LACI. HRL and lipoprotein LACI combine with lipoproteins in vitro while purified HepG2 LACI does not. I125-labeled HRL, injected into a rabbit, is cleared more slowly than I125-labeled HepG2 LACI, which may be due to attachment to lipoproteins in vivo. Preliminary evidence suggests that HRL is associated with vascular endothelium, possibly by attachment to glycosaminoglycans.
39
Caro, Florence, Nicole M. Place, and John J. Mekalanos. "Analysis of lipoprotein transport depletion in Vibrio cholerae using CRISPRi." Proceedings of the National Academy of Sciences 116, no. 34 (August 1, 2019): 17013–22. http://dx.doi.org/10.1073/pnas.1906158116.
Abstract:
Genes necessary for the survival or reproduction of a cell are an attractive class of antibiotic targets. Studying essential genes by classical genetics, however, is inherently problematic because it is impossible to knock them out. Here, we screened a set of predicted essential genes for growth inhibition using CRISPR-interference (CRISPRi) knockdown in the human pathogen Vibrio cholerae. We demonstrate that CRISPRi knockdown of 37 predicted essential genes inhibits V. cholerae viability, thus validating the products of these genes as potential drug target candidates. V. cholerae was particularly vulnerable to lethal inhibition of the system for lipoprotein transport (Lol), a central hub for directing lipoproteins from the inner to the outer membrane (OM), with many of these lipoproteins coordinating their own essential processes. Lol depletion makes cells prone to plasmolysis and elaborate membrane reorganization, during which the periplasm extrudes into a mega outer membrane vesicle or “MOMV” encased by OM which dynamically emerges specifically at plasmolysis sites. Our work identifies the Lol system as an ideal drug target, whose inhibition could deplete gram-negative bacteria of numerous proteins that reside in the periplasm.
40
Yan, Haizhao, Manabu Niimi, Fumikazu Matsuhisa, Huanjin Zhou, Shuji Kitajima, Yajie Chen, Chuan Wang, et al. "Apolipoprotein CIII Deficiency Protects Against Atherosclerosis in Knockout Rabbits." Arteriosclerosis, Thrombosis, and Vascular Biology 40, no. 9 (September 2020): 2095–107. http://dx.doi.org/10.1161/atvbaha.120.314368.
Abstract:
Objective: Apo (apolipoprotein) CIII mediates the metabolism of triglyceride (TG)-rich lipoproteins. High levels of plasma apoCIII are positively correlated with the plasma TG levels and increase the cardiovascular risk. However, whether apoCIII is directly involved in the development of atherosclerosis has not been fully elucidated. Approach and Results: To examine the possible roles of apoCIII in lipoprotein metabolism and atherosclerosis, we generated apoCIII KO (knockout) rabbits using ZFN (zinc finger nuclease) technique. On a normal standard diet, apoCIII KO rabbits exhibited significantly lower plasma levels of TG than those of WT (wild type) rabbits while total cholesterol and HDL (high-density lipoprotein) cholesterol levels were unchanged. Analysis of lipoproteins isolated by sequential ultracentrifugation revealed that reduced plasma TG levels in KO rabbits were accompanied by prominent reduction of VLDLs (very-low-density lipoproteins) and IDLs (intermediate-density lipoproteins). In addition, KO rabbits showed faster TG clearance rate after intravenous fat load than WT rabbits. On a cholesterol-rich diet, KO rabbits exhibited constantly and significantly lower levels of plasma total cholesterol and TG than WT rabbits, which was caused by a remarkable reduction of β-VLDLs—the major atherogenic lipoproteins. β-VLDLs of KO rabbits showed higher uptake by cultured hepatocytes and were cleared faster from the circulation than β-VLDLs isolated from WT rabbits. Both aortic and coronary atherosclerosis was significantly reduced in KO rabbits compared with WT rabbits. Conclusions: These results indicate that apoCIII deficiency facilitates TG-rich lipoprotein catabolism, and therapeutic inhibition of apoCIII expression may become a novel means not only for the treatment of hyperlipidemia but also for atherosclerosis.
41
Minamoto, Tomomi, Rosemary L. Walzem, Alexandra J. Hamilton, Steve L. Hill, Harold R. Payne, Jonathan A. Lidbury, Jan S. Suchodolski, and Jörg M. Steiner. "Altered lipoprotein profiles in cats with hepatic lipidosis." Journal of Feline Medicine and Surgery 21, no. 4 (June 4, 2018): 363–72. http://dx.doi.org/10.1177/1098612x18780060.
Abstract:
Objectives The aim of this study was to assess serum lipoprotein profiles using rapid single-spin continuous lipoprotein density profiling (CLPDP) in healthy control cats and cats with hepatic lipidosis (HL). Methods Analysis of serum lipoprotein profiles using the CLPDP was performed in 23 cats with HL and 20 healthy control cats. The area under the curve for each lipoprotein fraction, triglyceride (TG)-rich lipoproteins (TRLs), low-density lipoproteins (LDLs) and high-density lipoproteins (HDLs), was calculated. Serum cholesterol and TG concentrations were measured using a clinical chemistry analyzer. Results Serum cholesterol and TG concentrations were not significantly different between healthy control cats and cats with HL ( P = 0.5075 and P = 0.2541, respectively). LDL content was significantly higher in cats with HL than in healthy control cats ( P = 0.0001), while HDL content was significantly lower in cats with HL than in healthy control cats ( P = 0.0032). TRL content was not significantly different between the two groups ( P = 0.0699). The specific fraction (1.037–1.043 g/ml) within nominal LDL in serum distinguished healthy control cats from cats with HL with a sensitivity of 87% and a specificity of 90%. Conclusions and relevance Serum lipoprotein profiles were altered in cats with HL, even though serum cholesterol and TG concentrations were not significantly different compared with healthy control cats. The CLPDP might be a useful tool for assessing lipid metabolism in cats with HL.
42
Szczepanek, S. M., S. Frasca, V. L. Schumacher, X. Liao, M. Padula, S. P. Djordjevic, and S. J. Geary. "Identification of Lipoprotein MslA as a Neoteric Virulence Factor of Mycoplasma gallisepticum." Infection and Immunity 78, no. 8 (June 1, 2010): 3475–83. http://dx.doi.org/10.1128/iai.00154-10.
Abstract:
ABSTRACT Many lipoproteins are expressed on the surfaces of mycoplasmas, and some have been implicated as playing roles in pathogenesis. Family 2 lipoproteins of Mycoplasma pneumoniae have a conserved “mycoplasma lipoprotein X” central domain and a “mycoplasma lipoprotein 10” C-terminal domain and are differentially expressed in response to environmental conditions. Homologues of family 2 lipoproteins are Mycoplasma specific and include the lipoprotein of Mycoplasma gallisepticum, encoded by the MGA0674 gene. Comparative transcriptomic analysis of the M. gallisepticum live attenuated vaccine strain F and the virulent strain Rlow, reported in this study, indicated that MGA0674 is one of several differentially expressed genes. The MGA0674-encoded lipoprotein is a proteolytically processed, immunogenic, TX-114 detergent-phase protein which appears to have antigenic divergence between field strains Rlow and S6. We examined the virulence of an Rlow ΔMGA0674 mutant (P1H9) in vivo and observed reduced recovery and attenuated virulence in the tracheas of experimentally infected chickens. The virulence of two additional Rlow ΔMGA0674 mutants, 2162 and 2204, was assessed in a second in vivo virulence experiment. These mutants exhibited partial to complete attenuation in vivo, but recovery was observed more frequently. Since only Mycoplasma species harbor homologues of MGA0674, the gene product has been renamed “Mycoplasma-specific lipoprotein A” (MslA). Collectively, these data indicate that MslA is an immunogenic lipoprotein exhibiting reduced expression in an attenuated strain and plays a role in M. gallisepticum virulence.
43
Das, Sankar, Taisei Kanamoto, Xiuchun Ge, Ping Xu, Takeshi Unoki, Cindy L. Munro, and Todd Kitten. "Contribution of Lipoproteins and Lipoprotein Processing to Endocarditis Virulence in Streptococcus sanguinis." Journal of Bacteriology 191, no. 13 (April 24, 2009): 4166–79. http://dx.doi.org/10.1128/jb.01739-08.
Abstract:
ABSTRACT Streptococcus sanguinis is an important cause of infective endocarditis. Previous studies have identified lipoproteins as virulence determinants in other streptococcal species. Using a bioinformatic approach, we identified 52 putative lipoprotein genes in S. sanguinis strain SK36 as well as genes encoding the lipoprotein-processing enzymes prolipoprotein diacylglyceryl transferase (lgt) and signal peptidase II (lspA). We employed a directed signature-tagged mutagenesis approach to systematically disrupt these genes and screen each mutant for the loss of virulence in an animal model of endocarditis. All mutants were viable. In competitive index assays, mutation of a putative phosphate transporter reduced in vivo competitiveness by 14-fold but also reduced in vitro viability by more than 20-fold. Mutations in lgt, lspA, or an uncharacterized lipoprotein gene reduced competitiveness by two- to threefold in the animal model and in broth culture. Mutation of ssaB, encoding a putative metal transporter, produced a similar effect in culture but reduced in vivo competiveness by >1,000-fold. [3H]palmitate labeling and Western blot analysis confirmed that the lgt mutant failed to acylate lipoproteins, that the lspA mutant had a general defect in lipoprotein cleavage, and that SsaB was processed differently in both mutants. These results indicate that the loss of a single lipoprotein, SsaB, dramatically reduces endocarditis virulence, whereas the loss of most other lipoproteins or of normal lipoprotein processing has no more than a minor effect on virulence.
44
Reffuveille, Fany, Charlène Leneveu, Sylvie Chevalier, Yanick Auffray, and Alain Rincé. "Lipoproteins of Enterococcus faecalis: bioinformatic identification, expression analysis and relation to virulence." Microbiology 157, no. 11 (November 1, 2011): 3001–13. http://dx.doi.org/10.1099/mic.0.053314-0.
Abstract:
Enterococcus faecalis is a ubiquitous bacterium that is capable of surviving in a broad range of natural environments, including the human host, as either a natural commensal or an opportunistic pathogen involved in severe hospital-acquired infections. How such opportunistic pathogens cause fatal infections is largely unknown but it is likely that they are equipped with sophisticated systems to perceive external signals and interact with eukaryotic cells. Accordingly, being partially exposed at the cell exterior, some surface-associated proteins are involved in several steps of the infection process. Among them are lipoproteins, representing about 25 % of the surface-associated proteins, which could play a major role in bacterial virulence processes. This review focuses on the identification of 90 lipoprotein-encoding genes in the genome of the E. faecalis V583 clinical strain and their putative roles, and provides a transcriptional comparison of microarray data performed in environmental conditions including blood and urine. Taken together, these data suggest a potential involvement of lipoproteins in E. faecalis virulence, making them serious candidates for vaccine production.
45
Et al., Alkhafajy. "A Molecular and Biochemical Study for Cholesteryl Ester Transfer Protein (CETP) Taq1B in Iraqi Patients with Hyperlipidemia." Baghdad Science Journal 16, no. 3(Suppl.) (September 22, 2019): 0747. http://dx.doi.org/10.21123/bsj.2019.16.3(suppl.).0747.
Abstract:
Cholesteryl ester transfer protein gene contains some single nucleotide polymorphisms, which have been associated with serum high-density lipoprotein concentration and other lipoproteins. This study is done for determining of cholesteryl ester transfer protein polymorphism and evaluate its effect on serum lipid profile concentrations in some hyperlipidemic patients compared with healthy subjects in Salah Al-din governorate-Iraq. Blood samples were taken from (90) patients suffering from hyperlipidemia, and (70) samples that were apparently healthy controls. Serum lipid concentrations were measured by enzymatic assays. The polymorphism was genotyped using polymerase chain reaction restriction fragment length polymorphism analysis. The results showed that there was a significant decrease (P<0.05) in the frequency B2 allele, and B1B2, B2B2 genotype, and a significant increase (P<0.05) in the frequency B1 allele, and B1B1 genotype between patients and controls groups. There was a non-significant decrease in the levels of high density lipoproteins, total cholesterol, low density lipoproteins, and very low density lipoproteins levels, and non-significant increase in levels of triglycerides in individuals with the B1B1 genotype than in the B1B2 and B2B2 genotype. However, high density lipoproteins showed a significant decrease (P<0.001) between individuals with the B1B1 genotype and B2B2 genotype. Also, there was a non-significant difference in the levels of high density lipoproteins, total cholesterol, low density lipoproteins, and very low density lipoproteins levels, in individuals with the B1B2 genotype when compared with that of the B2B2 genotype.
46
Arfuso, Francesca, Francesco Fazio, Michele Panzera, Claudia Giannetto, Simona Di Pietro, Elisabetta Giudice, and Giuseppe Piccione. "Lipid and lipoprotein profile changes in newborn calves in response to the perinatal period." Acta Veterinaria 67, no. 1 (March 1, 2017): 25–32. http://dx.doi.org/10.1515/acve-2017-0003.
Abstract:
AbstractThe aim of this study was to evaluate the dynamic changes of serum lipid and lipoprotein profiles in 6 newborn calves during the first five days of life. From each calve blood sampling was performed daily starting from day 1 (after colostrum intake) until day 5 of life. Blood samples collected from each animal were tested for serum total lipids, phospholipids, non-esterified fatty acids (NEFAs), triglycerides, very low density lipoproteins (VLDLs), total cholesterol (Total-Chol), high density lipoproteins (HDLs) and low density lipoproteins (LDLs). One-way repeated measures analysis of variance (ANOVA) was applied to determine the effect of days of life on the studied parameters in calves. A statistically significant effect of days of life was found on all serum lipid and lipoprotein indices measured in calves with the exception of NEFAs that showed unchanged values throughout the monitoring period. The changes observed in calves during the early postnatal period are most likely due to the transition in energy sources, from a maternal nutrient supply comprising mainly carbohydrates and amino acids to the colostrum and milk diet rich in fat.
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Lewenza, Shawn, Musa M. Mhlanga, and Anthony P. Pugsley. "Novel Inner Membrane Retention Signals in Pseudomonas aeruginosa Lipoproteins." Journal of Bacteriology 190, no. 18 (July 18, 2008): 6119–25. http://dx.doi.org/10.1128/jb.00603-08.
Abstract:
ABSTRACT The ultimate membrane localization and function of most of the 185 predicted Pseudomonas aeruginosa PAO1 lipoproteins remain unknown. We constructed a fluorescent lipoprotein, CSFPOmlA-ChFP, by fusing the signal peptide and the first four amino acids of the P. aeruginosa outer membrane lipoprotein OmlA to the monomeric red fluorescent protein mCherry (ChFP). When cells were plasmolyzed with 0.5 M NaCl, the inner membrane separated from the outer membrane and formed plasmolysis bays. This permits the direct observation of fluorescence in either the outer or inner membrane. CSFPOmlA-ChFP was shown to localize in the outer membrane by fluorescence microscopy and immunoblotting analysis of inner and outer membrane fractions. The site-directed substitution of the amino acids at positions +2, +3, and +4 in CSFPOmlA-ChFP was performed to test the effects on lipoprotein localization of a series of amino acid sequences selected from a panel of predicted lipoproteins. We confirmed Asp+2 and Lys+3 Ser+4 function as inner membrane retention signals and identified four novel inner membrane retention signals: CK+2 V+3 E+4, CG+2 G+3 G+4, CG+2 D+3 D+4, and CQ+2 G+3 S+4. These inner membrane retention signals are found in 5% of the 185 predicted P. aeruginosa lipoproteins. Full-length chimeras of predicted lipoproteins PA4370 and PA3262 fused to mCherry were shown to reside in the inner membrane and showed a nonuniform or patchy distribution in the membrane. The optical sectioning of cells producing PA4370CGDD-ChFP and PA3262CDSQ-ChFP by confocal microscopy improved the resolution and indicated a helix-like localization pattern in the inner membrane. The method described here permits the in situ visualization of lipoprotein localization and should work equally well for other membrane-associated proteins.
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Kuchenhoff, A., B. Harrach-Ruprecht, and H. Robenek. "Interaction of apo E-containing lipoproteins with the LDL receptor-related protein LRP." American Journal of Physiology-Cell Physiology 272, no. 2 (February 1, 1997): C369—C382. http://dx.doi.org/10.1152/ajpcell.1997.272.2.c369.
Abstract:
The low-density lipoprotein (LDL) receptor-related protein (LRP) is a multifunctional cell surface receptor that interacts with apolipoprotein E (apo E)-rich lipoproteins, and alpha2-macroglobulin (alpha2-M) in the activated state (alpha2-M*). Whether LRP is a physiologically relevant lipoprotein receptor for naturally occurring apo E-rich lipoproteins, however, is still under discussion. To address this question, we isolated beta-migrating very low density lipoprotein (beta-VLDL) from rabbits by using gel filtration chromatography. Biochemical analysis of beta-VLDL subfractions demonstrated that we isolated apo E- and cholesterol-rich triglycerides with differences in composition and size. Binding and uptake characteristics of beta-VLDL subfractions and alpha2-M* on mouse peritoneal macrophages (MPM) and Hep G2 cells were examined by electron microscopy. One of the beta-VLDL subfractions, beta-VLDL(II), bound specifically to LRP on MPM and Hep G2. beta-VLDL(II) competed with the binding of alpha2-M* without addition of exogenous apo E. Furthermore, binding and uptake of beta-VLDL(II) and alpha2-M* were not affected by either lactoferrin or Ca2+-free medium. The results indicate that naturally occurring apo E-rich lipoproteins do exist and that they very likely interact with LRP via the same binding site as alpha2-M*.
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Yao, Ji-Jin, Xiao-Jun He, Wayne R. Lawrence, Wang-Jian Zhang, Jia Kou, Fan Zhang, Guan-Qun Zhou, Si-Yang Wang, and Ying Sun. "Prognostic Value of Circulating Lipoprotein in Patients with Locoregionally Advanced Nasopharyngeal Carcinoma." Cellular Physiology and Biochemistry 48, no. 1 (2018): 285–92. http://dx.doi.org/10.1159/000491728.
Abstract:
Background/Aims: Lipoproteins have been reported to be associated with prognosis in various cancers; however, the prognostic value of lipoproteins in patients with nasopharyngeal carcinoma (NPC) remains largely unknown. We aim to asses the role of circulating lipoproteins in locoregionally advanced NPC patients. Methods: Between October 2009 and August 2012, a total of 1,081 patients with stage III-IVB NPC were included in the analysis. Circulating high-density lipoprotein (HDL) and low-density lipoprotein (LDL) are the two key lipoproteins, which were measured at baseline. Receiver operating characteristic (ROC) curve analysis was used to evaluate different cut-off points for lipoproteins. Actuarial rates were performed using Kaplan–Meier methods and the log-rank test. Results: The cutoff points of HDL, LDL, and LDL/HDL ratio were 1.17 mmol/L, 3.75 mmol/L, and 2.73, respectively. At 5 years, high HDL (> 1.17 mmol/L) was significantly associated with better overall survival (OS, 86.6% vs. 78.9%; P=0.004), distant metastasis-free survival (DMFS, 86.9% vs. 80.8%; P=0.004), locoregional relapse-free survival (LRFS, 90.8% vs. 85.4%; P=0.010), and progression-free survival (PFS, 79.1% vs. 70.2%; P= 0.001) than low HDL (≤1.17 mmol/L). In contrast, high LDL (> 3.75 mmol/L) tend to be inferior OS (79.1% vs. 84.9%; P= 0.016) in compassion with low LDL (≤3.75 mmol/L). Likewise, patients with high LDL/HDL ratio (> 2.73) tend to be inferior OS (79.3% vs. 86.9%; P=0.001), DMFS (81.9% vs. 86.5%; P=0.030), and PFS (72.6% vs. 77.8%; P= 0.034) than those of low LDL/HDL ratio (≤2.73). In multivariate analysis, baseline HDL was found to be a significant prognostic factor for LRFS (HR= 0.65; 95% CI, 0.45-0.93; P= 0.019) and PFS (HR=0.75; 95% CI, 0.58-0.98; P= 0.034). Conclusions: Circulating HDL is significantly associated with treatment outcomes in patients with locoregionally advanced NPC. We suggest that HDL measurements will be of great clinical significance in the management of NPC.
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Roche, D., V. Atger, N. T. Le Quang, A. Girard, and O. G. Ekindjian. "Polyacrylamide gel electrophoresis in quantification of high-density lipoprotein cholesterol." Clinical Chemistry 31, no. 11 (November 1, 1985): 1893–95. http://dx.doi.org/10.1093/clinchem/31.11.1893.
Abstract:
Abstract We evaluated a method for quantifying high-density lipoprotein cholesterol in plasma, based on electrophoretic migration of the prestained (with Sudan Black III) sample through a discontinuous polyacrylamide++ gel and densitometric integration of the stain associated with each class of lipoprotein. With this method, operations can be carried out on all types of lipoproteins over a broad range of concentrations. Overloading with very-low and low-density lipoproteins did not affect reliability within a wide range of HDL concentrations (0.45 to 16.60 mmol/L). Results for 22 individual plasma samples from normal and dyslipemic subjects correlated well with those by ultracentrifugal analysis (r=0.96; Student's t= 0.90, p > 0.30). We conclude that this method is reliable, sensitive, and accurate, It may be used for simultaneously typing dyslipoproteinemias and assaying HDL cholesterol.